How to Identify a Spider: Brown Widow vs Black Widow

Identifying a spider, especially distinguishing between a brown widow and a black widow, can be a challenging task due to their similar characteristics. Here are the key features and steps to accurately identify which spider you've encountered.

1. Color and Markings

Brown Widow (Latrodectus geometricus): Tends to have a light brown or tan body color. Features a notable orange or yellow hourglass marking on the underside of its abdomen, though this may be less pronounced compared to the black widow. The legs are usually adorned with darker bands.

Black Widow (Latrodectus mactans): Characteristically has a shiny black body. Has a prominent red hourglass marking on the underside of the abdomen, which can sometimes appear orange. The legs are long and slender with no visible banding.

2. Size

Both spiders are generally similar in size, typically around 1.5 inches in total leg span. However, the black widow tends to have a more robust and rounded body compared to the brown widow.

3. Habitat

Brown Widow: Often found in gardens, woodpiles, and areas close to human dwellings. Prefer more open and sunny areas.

Black Widow: Commonly found in dark, sheltered areas such as woodpiles, sheds, and basements.

4. Behavior

Both types of widow spiders are generally reclusive and will only bite in self-defense. A black widow may exhibit a more aggressive defensive behavior if threatened, whereas the brown widow tends to be more docile.

5. Web Structure

Both spiders create irregular webs, but:

Brown Widow: Web is generally less tightly woven and more chaotic.

Black Widow: Web tends to be more organized and intricate.

6. Geographic Range

The prevalence of each species varies based on location:

Brown Widow: More common in warmer climates.

Black Widow: Found in various regions across North America.

Conclusion

If you are unsure of the type of spider you've encountered, it is best to treat any bite as potentially serious and seek medical attention. Observing the spider's color, markings, and behavior can help you make a more accurate identification. If possible, taking a clear photo can also aid in later identification.